Cordlock structures adapted to be applied to the ends of headrails for locking operating cords of a blind assembly are known where the structure comprises a base portion for fixing the structure to the end of a headrail and a cap portion containing a cord locking means where the cap extends in a direction away from the headrail. The cap and base portions conventionally comprise a single unitary member which may be molded from a plastic material. Because the structure comprises a unitary member, the cordlock structure for use with one end of a headrail is different from and is a mirror image of the cordlock structure used at the opposite end of a headrail such that the two structures are not interchangeable. This of necessity requires an inventory of two separate cordlock structures to accommodate a blind assembly where it may be desirable, or necessary because of space limitations, to have blind operating cords positioned at a particular one of the two ends of a headrail supporting the blind assembly.
Some cordlock structures have comprised separate base members and cap members containing cord locking means where the cap members may be interchanged on the base member and where the base member may be fixed to either end of a headrail to accommodate desired positioning of blind operating cords. See for example the cordlock structure as disclosed in European Patent Application Ser. No. 059,807 published Sept. 15, 1982. Even so, such structure requires use of two separate and different cap portions which are mirror images of one another in order that the cordlock structure may be positioned on either end of a headrail thus increasing inventory of cap portions.
Conventional cordlock structures often include a locking means comprising a locking dog assembly made up of a long first arm pivotally connected to the cap portion and a short arm pivotally connected to the long arm. Each arm has a locking portion on the distal end thereof adapted to lockingly engage with blind operating cords passing therebetween and the pivot axes of the two arms are positioned inside of the path of the operating cords through the cap portion with respect to the blind assembly. In some cordlock structures having this type of locking means, it is necessary in order to lower the blind assembly to pull the operating cords slightly in a vertical direction beneath the locking means, and then release the cords under control of the operator until the blind is lowered the desired amount after which the operator stops the cords with his hand and pulls the cords away from the blind assembly in order to lock the locking means.
In order to raise the blind assembly with this type of locking means, the cords are pulled either downwardly or to one side or outwardly of the blind assembly and then locked in the same manner as in lowering the blind assembly. A problem with this structure however is that if the operator accidentally releases an operating cord, except at the designated locking position where the cord is pulled away from the plane of the blind assembly, the blind assembly supported by the cord will fall to a tilted or fully down position.
Cordlock structures having the locking means as described above could be made to automatically lock when the operating cord drops or falls to a vertical position and be unlocked by moving the cords in a direction towards the plane of the blind assembly. This would require that the cap portion containing the locking means be positioned sufficiently away from the plane of the blind assembly so that there is room to move the operating cord towards the blind assembly without interferring with the blind asembly. This positioning of the cap portion a sufficient distance away from the plane of the blind assembly would result in the cordlock structure being larger than is aesthetically desirable.
Cordlock structures are conventionally made of plastic moldings and because of expense and color retention characteristics, plastics are often used which do not have good wear resistant properties. Modern blind assemblies have small diameter operating cords to improve the appearance of the blind assembly, and where the blind assembly is of substantial weight, these small diameter cords may wear and gouge into the plastic material comprising the cordlock assembly. Because of expense of material, and difficulty in coloring and color retention of some plastic materials, it often is not feasible to make the cordlock structure of highly wear resistant structure.
It is therefore an object of my invention to provide for a cordlock structure which will comprise only two parts, namely a base member and a separate cap member which may be applied to either end of a headrail and on either side of a headrail thus reducing inventory of parts.
It is a further object of my invention to provide for a cordlock structure which will have a locking means which will automatically move to a locked position when operating cords beneath the locking means are moved to a vertical position and which may be moved to an unlocked position by moving the cords away from the plane of the blind assembly.
It is a further object of my invention to provide for a cordlock structure which may comprise an inexpensive plastic material having desired color and color retention properties and which at the same time will have wear resistant surfaces to prevent wear or gouging by blind operating cords.